Expression of Foreign Gene in Mycobacterium Regulated by Human Mycobacterium Tuberculosis Heat Shock Protein 70 Promoter

The DNA fragments of 150bp length promoter 0f human Mycobacterium(M.) tuberculosis heat shock protein (hsp)7O and 650bp length foreign gene, the Schistosoma japonicum glutathione S-transferase(Sj26GST)gene,were obtained by amplification with polymerase chain reaction. And the 150p DNA sequence upstream initiation codon ATG of the human M. tuberculosis hsp7O promoter that contains the sequence TTGAG and ATCATA which consensus with E. coli promoter's -35 and-10 region respectively, as well as ribosome binding site GGAGG at position-12-8 upstream the ATG were determined by SangerDideoxyribonucleotide-mediated chain-termination method-Then, the human M. tuberculosis hsp70 promoter and Sj26GST cDNA were cloned into E. coli-mycobacteria shuttle plasmid pBCG-2000 to construct E. coli-Mycobacterium expression shuttle plasmid pBCG- Sj26 that can express Sj26GST gene.The M. smegmatis were electroporated and the positivecolonies were selected by kanamycin-The M.smegmatis containing the vector pBCG-Sj26 can be induced by heating and hydrogen peroxide (H2O2) to express GST. The molecular weight of the recombinant GST(rGST) was 26000. The rGST contents that were about 10 percent of the total bacterial protein were analyzed by density scanning after running SDS-PAGE. This study would provide scientific evidences for application of hsp70 promoter in expressing foreign gene in mycobacterium and development of mycobacterium as multiple-valent vectoral vaccine.

Cloning, expression profiling and promoter functional analysis of bone morphogenetic protein 2 in the tongue sole(Cynoglossus semilaevis)

BMP2 plays crucial roles in vertebrate developmental process and acts as a bone inducer during osteogenesis. We present here the molecular cloning of bmp2 cDNA from the marine flatfish Cynoglossus semilaevis, and the analysis of bmp2 expression profiling and promoter function. The full length of bmp2 cDNA sequence is 2 048 bp,which encodes a protein of 422 amino acids. Tissue expression distribution of bmp2 was examined in 14 tissues of mature individuals by quantitative real time PCR（qRT-PCR）. The results revealed that bmp2 was expressed ubiquitously, and the highest expression level was detected in the spinal cord. Moreover, bmp2 expression levels were detected at 15 sampling time points of early developmental stages（egg, larva, juvenile and fingerling stages）.The highest expression level of bmp2 was observed at the gastrula stage, which was about ten times higher than those at the other three embryo stages. Whole-mount in situ hybridization showed that the bmp2 signal was strongly detected at the location of the crown-like larval fin, heart and liver, and slightly expressed in the notochord at one day post hatch（dph）; then the expression of bmp2 started to be concentrated in notochord at three dph. Subsequently, we characterized the 5′-flanking region of bmp2 by testing the promoter activity by Luciferase reporter assays. Positive regulatory region was detected at the location of –179 to ＋109. The predicted transcription factor binding sites（E-box binding factors, zinc finger transcription factor, etc.） in this region might participate in the transcriptional regulation of the bmp2 gene.

Expression in Arabidopsis of a Strawberry Linalool Synthase Gene Under the Control of the Inducible Potato PI2 Promoter

To investigate the role of inducible linalool in Arabidopsis-insect interactions, the FANES 1 linalool synthase （LIS） cDNA from strawberry with plastid targeting and a synthetic intron （LIS＇） was placed under the control of the wound inducible proteinase inhibitor 2 （PI2） promoter from potato. The construct pBin-PPi2-LIS＇ was transformed to Arabidopsis thaliana ecotype Columbia 0. Kanamycin resistant TO seedlings were confirmed for the presence and transcription of the LIS＇ gene by PCR analysis on genomic DNA and by RT-PCR analysis on RNA. Genomic and RT-PCR products were sequenced to confirm correct splicing of the synthetic intron. The expression of active linalool synthase by the PPI2-LIS＇ gene construct in the transgenic lines was assessed by measuring linalool emission using solid phase micro-extraction （SPME） GC-MS measurements after induction with methyl jasmonate. Among 30 tested independent T2 transgenic lines, 10 exhibited linalool production. Linalool expression could be induced by methyl jasmonate treatment, but not by diamondback moth larvae.

GFAP promoter directs lacZ expression specifically in a rat hepatic stellate cell line

AIM： The GFAP was traditionally considered to be a biomarker for neural gila （mainly astrocytes and nonmyelinating Schwann cells）. Genetically, a 2.2-kb human GFAP promoter has been successfully used to target astrocytes in vitro and in vivo. More recently, GFAP was also established as one of the several makers for identifying hepatic stellate cells （HSC）. In this project, possible application of the same 2.2-kb human GFAP promoter for targeting HSC was investigated. METHODS： The GFAP-lacZ transgene was transfected into various cell lines （HSC, hepatocyte, and other nonHSC cell types）. The transgene expression specificity was determined by X-gal staining of the β-galactosidase activity. And the responsiveness of the transgene was tested with a typical pro-fibrotic cytokine TGF-β1. The expression of endogenous GFAP gene was assessed by real-time RT-PCR, providing a reference for the transgene expression. RESULTS： The results demonstrated for the first time that the 2.2 kb hGFAP promoter was not only capable of directing HSC-specific expression, but also responding to a known pro-fibrogenic cytokine TGF-β1 by upregulation in a doseand time-dependent manner, similar to the endogenous GFAP. CONCLUSION： In conclusion, these findings suggested novel utilities for using the GFAP promoter to specifically manipulate HSC for therapeutic purpose.

Molecular characterization and expression analysis of Triticum aestivum squamosa-promoter binding protein-box genes involved in ear development

Wheat （Triticum aestivum L.） is one of the most important crops in the world. Squamosa-promoter binding protein （SBP）-box genes play a critical role in regulating flower and fruit development. In this study, 10 novel SBP-box genes （TaSPL genes） were isolated from wheat （（Triticum aestivum L.） cultivar Yanzhan 4110）. Phylogenetic analysis classified the TaSPL genes into five groups （G1-G5）. The motif combinations and expression patterns of the TaSPL genes varied among the five groups with each having own distinctive characteristics： TaSPL20/21 in G1 and TaSPL17 in G2 mainly expressed in the shoot apical meristem and the young ear, and their expression levels responded to development of the ear; TaSPL6/15 belonging to G3 were upregulated and TaSPL1/23 in G4 were downregulated during grain development; the gene in G5 （TaSPL3） expressed constitutively. Thus, the consistency of the phylogenetic analysis, motif compositions, and expression patterns of the TaSPL genes revealed specific gene structures and functions. On the other hand, the diverse gene structures and different expression patterns suggested that wheat SBP-box genes have a wide range of functions. The results also suggest a potential role for wheat SBP-box genes in ear development. This study provides a significant beginning of functional analysis of SBP-box genes in wheat.

Cloning of Soybean 24 kDa Oleosin Gene and Its Transient Expression as a Carrier for Foreign Protein

The genomic DNA sequence encoding soybean 24 kDa oleosin and its promoter were cloned andanalyzed for investigation of the potentials of the oleosin acted as a carrier forproduction of recombinant proteins in plant. The -300 box, GA-rich, G-box, SEF-3, SEF-4, RY box, ABA box, CAn and TATA box were found in the upstream region of the soybeanoleosin gene, which shows the functional oleosin promoter available. Homology comparisonreveals that the soybean 24 kDa oleosin shares the highest identity with the soybeanoleosin isoform A (U09118, GenBank), reaching to 98.4% in nucleotide. A soybean oleosin-hirudin fusion gene driven by the oleosin promoter was constructed and inserted intoplant binary expression vector. The intact tobacco plantlets were transformed by meansof vacuum infiltration approach, with the Agrobacterium tumefaciens harboring the abovevector. The transient correct expression of oleosin-hirudin fusion gene was identifiedby SDS/PAGE, western blotting and enterokinase treatment.

Functional analysis of the larval serum protein gene promoter from silkworm,Bombyx mori.

The regulation region of larval serum protein gene, Bombyx mori. (BmLSP), consisting of the first intron, the first exon, the central promoter region and 5′-upstream region, is cloned from genomic DNA from the silkworm va-riety of Suju譓inghu. Using PCR and restriction endonu-clease methods, a series of luciferase reporter plasmids, driven by different length of BmLSP promoters, are con-structed. Via the transient expression system in BmN cells, the effects of the regulation elements and foreign insect hor-mones on the BmLSP promoter activity are investigated. The results demonstrate that the promoter activity of BmLSP is 5.8- or 4.4-fold higher than that of BmLSPs whose first in-tron or the element in 5′-upstream region harboring the homologous sequence with the first intron of light-chain fib-roin gene (EHIF) is deleted, respectively, suggesting that both the first intron and EHIF contain the main positive cis-acting elements. However, the inactive mariner transposable ele-ment (MTE) in 5′-upstream region presents a negative effect. Furthermore, the effects of juvenile hormone analogue (JHA) on the BmLSP promoter activity show a typical dose-dependent manner, that is, low concentration treat-ments increase the BmLSP promoter activity and high con-centration treatments decrease it. Meanwhile, insect ecdy-sone (MH) treatments present no significant effect.

Genome-wide identification,phylogeny and expression analysis of the SBP-box gene family in maize(Zea mays)

The SQUAMOSA promoter binding protein （SBP）-box genes encode a kind of plant-specific transcription factors （TFs） and play important roles in the regulation of plant development. In this study, a genome-wide characterization of this family was conducted in maize （Zea mays）. Thirty-one SBP-box genes were identified to be distributed in nine chromosomes and 16 of them were complementary to the mature ZmmiR156 sequences. All the Z. mays SBP （ZmSBP） genes were classified into two clusters with eight subgroups according to the phylogenetic analysis of proteins, which were consistent with the pattern of exon-intron structures. The phylogenetic tree of the ZmSBP, Oryza sativa SBP-like （OsSPL） and Arabidopsis thaliana SBP-like （AtSPL） genes were constructed and all the SBP-box genes were divided into eight groups, which was the same as the classification of ZmSBP genes. The comparision of the expression profiles of all SBP-box genes in these three species indicated that most orthologous genes had similar expression patterns. The results from this study provided a basic understanding of the ZmSBP genes and might facilitate future researches for elucidating the SBP-box genes function in maize.

Western blot detection of PMI protein in transgenic rice

Phosphomannose isomerase （PMI） encoding gene manA is a desirable selective marker in transgenic research. Under- standing of its expression patterns in transgenic plant and establishing highly sensitive detection method based on immunoassay have great impacts on the application of PMI. In this study, PMI-specific monoclonal antibodies were generated using recombinant protein as immunogen, and could be used in Western blot to detect as little as 0.5 ng His-tagged PMI protein or rice expressed PMI protein in sample accounted for 0.4% of single rice grain （about 0.08 mg）. PMI protein driven by CaMV-35S promoter was detected in dozens of tested tissues, including root, stem, leaf, panicle, and seed at all developmental stages during rice growing, and PMI protein accounted for about 0.036% of total protein in the leaves at seedling stage. The established method potentially can be used to monitor PMI protein in rice grains.

Genetic Modification of Baculovirus Expression Vectors

As a protein expression vector, the baculovirus demonstrates many advantages over other vectors. With the development of biotechnology, baculoviral vectors have been genetically modified to facilitate high level expression of heterologous proteins in both insect and mammalian cells. These modifications include utilization of different promoters and signal peptides, deletion or replacement of viral genes for increasing protein secretion, integration of polycistronic expression cassette for producing protein complexes, and baculovirus pseudotyping, promoter accommodation or surface display for enhancing mammalian cell targeting gene delivery. This review summarizes the development and the current state of art of the baculovirus expression system. Further development of baculovirus expression systems will make them even more feasible and accessible for advanced applications.

A preliminary study on the cloning and expression of human papiilomavirus type 18 E6 gene in Escherichia coli

We have cloned the E6 gene of human papillomavirus type 18 into anexpression plasmid pBD2.One of the recombinant plasmids (named pDV11) wasidentified by DNA analysis and protein product analysis.It could express a newprotein whose molecular weight correspods well with the expected one.Afterpurification,the expressed protein showed a positive result in countercurrentimmuno-electrophoresis with anti-β-gal serum and was proved to be the expectedβ-gal/E6 fusion protein.The physical map of pDV11 was also prepared.

Analysis of the Cotton E6 Promoter

An E6 gene from sea island cotton （Gossypium barbadense） was expressed specifically in cotton fiber cells to transfer functions to cultivated species for better transgenic engineering. The regulatory activity of the E6 promoter region was then studied by isolating a 614-bp fragment of the 5＇-flanking region from upland cotton （Gossypium hirsutum CR1-12） to produce a green fluorescent protein （GFP） reporter construct for analysis of tissue-specific expression in transgenic tobacco seedlings. Fluorescent analyses indicate that the relatively short E6 promoter is sufficient to direct green fluorescent protein expression specifically in the leaf trichomes （hair cells） of the transgenic tobacco plants. As cotton fibers are also unicellular trichomes that differentiate from epidermal cells of developing cotton ovules, the result suggests that the relatively short E6 promoter can serve as a fiber-specific expression promoter for genetic engineering to improve cotton fiber quality.

Characterization of two constitutive promoters RPS28 and EIF1 for studying soybean growth,development,and symbiotic nodule development

Native promoters that can drive high and stable transgene expression are important tools for modifying plant traits.Although several such promoters have been reported in soybean(Glycine max),few of them function at multiple growth and development stages and during nodule development.Here,we report that the promoters of 40S RIBOSOMAL PROTEIN SMALL SUBUNIT S28(RPS28)and EUKARYOTIC TRANSLATION INITIATION FACTOR 1(EIF1)are ideal for high expression of transgene.Through bioinformatic analysis,we determined that RPS28 and EIF1 were highly expressed during soybean growth and development,nodule development,and various biotic and abiotic stresses.Fusion of both RPS28 and EIF1 promoters,with or without their first intron,with the reporter geneβ-GLUCURONIDASE(uidA)in transgenic soybean,resulted in high GUS activity in seedlings,seeds,and nodules.Fluorimetric GUS assays showed that the RPS28 promoter and the EIF1 promoter yielded high expression,comparable to the soybean Ubiquitin(GmUbi)promoter.RPS28 and EIF1 promoters were also highly expressed in Arabidopsis thaliana and Nicotiana benthamiana.Our results indicate the potential of RPS28 and EIF1 promoters to facilitate future genetic engineering and breeding to improve the quality and yield of soybean,as well as in a wide variety of other plant species.

Contruction of the Genetic Engineering Strain Expressed Nontoxic ST_1-LT_B Fusion Protein Against Enterotoxigenic Eschenichia coli

Thermostable enterotoxinⅠ(ST1) mutant genes and thermolabile enterotoxin B subunit (LTB)genes were amplified by PCR from plasmids of Eschenichia coli C83902. The recombinantexpression plasmid pZST3LTB containing ST1-LTB fusion gene was constructed by recombinantDNA technique and then transformed into Escherichia coli BL21(DE3). The ST1-LTB fusionprotein was highly expressed in recombinant strain BL21(DE3)(pZST3LTB) and the fusionprotein was about 38.53% of total cellular protein by SDS-PAGE and thin-layer gelscanning analysis. More important, mice immunized with crude preparation containing thefusion protein inclusion bodies or inactivated recombinant strain produced antibodiesthat were able to recognize ST1 in vitro. These sera antibodies were able to neutralizethe biological activity of native ST1 in the suckling mouse assay. Hence the ST1-LTBfusion protein was nontoxic and immunogenic, the constructed recombinant strain BL21(DE3)(pZST3LTB) could be used as a candidate of vaccine strain.

含P_RP_L启动子的原核高效表达载体的组建及其应用

我们组建了一个含P_RP_L自动子的原核高效表达载体,它同时含有cI调控基因、多酶切点和两个强的转录终止序列。带起始密码子ATG的外源基因可以插入启动子下游的多酶切点,表达非融合蛋白,产品可供临床使用。我们实验室已用它成功地表达了人γ干扰素、人白细胞介素-2和人肿瘤坏死因子等,表达量均占菌体总蛋白的20％以上。

一种带增强子的原核高效表达载体的构建及初步应用

构建的 pTO T7大肠杆菌高效融合表达载体 ,调控序列中有一个Ω序列和一个T7启动子串联 ;多克隆位点 (MCS)包括 8个常用酶切位点 ;可进行融合表达或者非融合表达 ,根据不同的需要加以选择 ;融合蛋白N端为T7g10的 12个起始氨基酸 ,C端为His标签 ;含kan抗性基因作为选择标记。将增强型绿色荧光蛋白 (EGFP)基因克隆至 pTO T7载体 ,在E .coli中的表达结果表明 ,融合EGFP达到菌体总蛋白量的 5 0 %以上 ,90 %以上的融合蛋白以可溶性形式存在 ,融合后的EGFP仍保持原有的荧光性质。与同时构建的不含Ω序列的 pT T7载体的表达产量的比较研究结果表明 ,Ω序列在 pTO T7载体中能显著提高表达效率。

低温菌启动子分析及异源蛋白高效表达

在已构建的能在低温菌和E.coli中正常复制的启动子探针质粒的基础上,筛选到了强启动子,通过RT-PCR评估了启动子活性,并通过引物延伸实验确定了转录起始位点和启动子核心序列。利用其中最强的启动子构建了低温蛋白表达质粒,使一个热不稳定α-淀粉酶在低温下(7℃)得到了高效表达,表达量达胞外总蛋白的35%。显示出该表达系统具有高效表达热不稳定蛋白质的潜在应用价值。

食品级分泌表达载体的构建及报告蛋白在乳酸乳球菌中的表达

为构建乳酸乳球菌食品级分泌表达载体,通过PCR扩增质粒pMG36e的p32启动子片段及乳酸乳球菌MG1363未知分泌蛋白(Usp45)基因的核糖体结合位点、分泌信号肽和成熟肽前11个氨基酸的编码序列(SPusp45),克隆到食品级载体pSH91中,构建食品级分泌性表达载体pSQ;克隆报告基因金黄色葡萄球菌核酸酶(NucA)成熟肽的编码序列nucA到pSQ中分泌信号后,转化乳酸乳球菌MBP71,构建了乳酸乳球菌食品级分泌性表达系统Llactis/pSQ-nucA;通过TB-D法和酶谱法检测Llactis/pSQ-nucA的表达形式、表达量并与以前构建的Llactis/pSQZ-nucA系统表达能力进行比较,结果发现Llactis/pSQ-nucA能够分泌性表达NucA,分泌性表达的NucA量大约是胞内NucA的10倍;Llactis/pSQ-nucA的表达量高于lactis/pSQZ-nucA。为进一步目的蛋白的的分泌性表达及食品级疫苗的研制奠定了基础。

棉花GbGAI2启动子克隆及表达分析

通过染色体步移方法获得棉花GbGAI2基因的上游2378bp启动子序列,并对其进行生物信息学分析。将启动子序列与GUS基因连接,转化拟南芥,并对转化植株进行组织化学分析。结果表明,启动子区域内含有丰富的与光信号途径、激素信号途径(GA/IAA)、逆境胁迫相关等的顺式作用元件。在外施GA条件下,启动子活性增强。通过对启动子表达模式的分析表明,棉花GbGAI2基因在GA信号途径中起很大作用。

应用人延伸因子1α亚基启动子和人工转录激活因子提高外源基因在CHO细胞中的表达

表达载体的设计对于提高外源基因在哺乳动物细胞中的表达量十分重要 .而表达载体中最为重要的元件是启动子 .一些常用病毒来源的启动子 ,如巨细胞病毒即早期启动子 (PCMV IE)仅在S期激活 ,应用这类启动子表达外源蛋白需要宿主细胞不停增殖 ,这对于连续持久大规模培养的宿主细胞不现实 .而人延伸因子 1α亚基启动子 (PEF 1α)不受细胞周期限制 ,且启动子强度高于PCMV IE,对于大规模外源蛋白的生产较为理想 .首先构建了基于PEF 1α启动子的哺乳动物细胞表达载体pED5 ,在增殖缓慢的CHO细胞中 ,此载体表达外源蛋白的能力是应用PCMV IE启动子表达载体的 4 1倍 .由于启动子一般仅能决定基因转录的本底水平 ,而转录激活因子 (transcriptionactivators)对基因转录的影响更大 ,所以另把两个人工转录激活结构域AH和VP2接到λ噬菌体cⅠ蛋白的C端 ,它们通过cⅠ蛋白结合于已插入到PEF 1α启动子的TATA框上游约 2 0 0bp的λ噬菌体OR2 OR1序列上 ,而被“征募”到PEF 1α启动子TATA框附近 ,从而促进基因的转录 .把上述元件均整合进一个表达载体中 ,构建了两个新型表达载体pER AH和pER VP2 .pER AH表达外源蛋白的能力比不含转录激活因子的表达载体略高 ,而pER VP2表达外源蛋白的能力则比不含转录激活因子的表达载体高